So, this appears to be a popular topic hear. I bought my Civic used Jan of 11. What's been done:

I had the dealer I bought it from change the timing belt, water pump, and tensioners right away before it left the lot. Since they didn't know if the timing belt had been done by the previous owner. Towards the end of Feb. to mid March. I noticed the thermostat would go up during low idle. I had my regular mechanic look at it ( a few times... ). First he replaced the thermostat. That didn't work. I then asked about flushing the heater core. This actually seemed to fix it until June. The first time the temps got over 85 the over heating issue came back. Took it to the local honda dealer hoping they could fix it and it would be gone. They topped the coolant off first. The issue came back. Then they were sure it was the head gasket. They said they checked the head to make sure it wasn't warped. Now four months later. The over heating issue is back during low rpm situations again.

Looking around at forums I can say the thermostat and water pump are probably not OEM. I know the radiator cap hasn't been replaced. Both fans do kick on and bring the temp down when the car is just sitting in park and idling. The heater is blowing cold air currently just before the temp gauge starts to go up. Does anyone have any thoughts on what else could be causing this?

Thanks,
Will

 

when it "overheats, where on the temp gauge doe the needle hit?

 

It did this once Monday night. I'd say it goes to about the 3/4 point, just to the point where the needle is almost to the top of the thermometer symbol. This is the pretty close to where it was going when this started last spring. During the summer on days where the temp was over 85 degrees, the needle would go to just one or two dashes below hot. Generally if it was under 85 degrees during the summer it would go to about the 3/4 point. During the week I don't drive much (4 to 8 miles a day), and it's all city driving so I might see it again before Friday if I'm stopped at a stop light.

 

I would suggest perusing through this thread for possible solutions: https://honda-tech.com/forums/honda-civic-2001-2005-78/01-05-civic-cooling-system-q-overheating-fans-inoperable-etc-2889523/

 

Just an update on this. I replaced the radiator cap w/ an oem cap I picked up at the local Honda Dealer. Things I noticed when I did this Thursday night. The coolant reservoir was completely empty. The radiator was also a little low. I picked up some Honda coolant when I got the radiator cap. Used about 1/2 gallon to fill the reservoir and radiator.

I picked up a oem thermostat on Friday, and replaced that today. Just a note here. I've been working away from home, and drove back about 200 miles Friday night. Didn't loose a drop of coolant from what I could tell. Before I put the thermostat in, I dropped it in to boiling water to compare it with the old non-oem thermostat. The oem opened up sooner and wider than the non-oem one. Not sure what the temp was since I didn't have a thermometer handy. I also noticed the lower radiator hose seemed cold before replacing the thermostat with an oem one.

I'm hoping this fixes it, but loosing a 1/2 gallon of coolant makes me think there's probably something else that's the actual problem. If anyone has any thoughts let me know.

 

As I stated before, you should take a gander at the thread I posted regarding coolant issues.

But, in your case if you have lost coolant, you either have a leak through the radiator cap (because you replaced yours) or a potential head gasket problem. Also, your coolant overflow bottle shouldn't be FULL of coolant. It should only be about 1/4 to 1/2 full.

 

headgasket is blown.. cylinder 2 seems to be the culprit. have your mechanic do a leakdown test on cylinder 2 with a funnel ontop of the radiator.. you'll see constant bubbles coming from the radiator.

 

How can you know it's cylinder 2? If it's the head gasket, I guess I'd be curious why I'm not seeing these: (white smoke from the exhaust, milky colored oil, coolant overflowing the reservoir).

While I suppose it's not impossible. I'd like to think that a head gasket shouldn't go bad in less than 4 months. I'm probably playing with fire. I put on about 350 highway miles (Friday to Sunday night) this weekend. I haven't checked yet today, but as of yesterday I haven't lost any coolant after replacing the radiator cap and thermostat.

 

Just keep checking your coolant and hope it was the radiator cap. Needing a 1/2 gallon of coolant is a lot though.

How much coolant did you lose when you changed the thermostat?

Head gaskets going shortly after being replaced isn't all the uncommon, it's one of those if it aint broke don't fix it things.

 

I didn't loose much coolant when I replaced the thermostat. Somewhere under a quart if I had to guess. Seems like there's well over a quart in the gallon jug of coolant I bought.

 

Just a follow up to this. Dropped my civic off at the local honda dealership where I'm living now after I noticed loosing about a 1/2 cup of coolant every 300 miles or so from weekend drives, they also suspect it's the head gasket. So Monday this goes into get a new head gasket again, have the head milled, and new bolts put in.

I'm curious, how often do others with civics see their head gaskets go bad? Is this something that typically happens every 100k miles, or do people in general see this more often?

 

Pre 7th gen the HG's are strong and will go a long time.

Unfortunately in the 7th gen's it's a very common problem. Since you already had the HG replaced once I assume the head is probably warped, either from driving the car while overheating too much or possibly from removing/installing the head when you had the first HG done. Either someone messed up when checking the head or you got a defective head gasket. Crappy luck.

 

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